Generally, a wind turbine includes a tower, a nacelle mounted on the tower, and a rotor coupled to the nacelle. The rotor typically includes a rotatable hub and a plurality of rotor blades coupled to and extending outwardly from the hub. Each rotor blade may be spaced about the hub so as to facilitate rotating the rotor to enable kinetic energy to be transferred from the wind into usable mechanical energy, and subsequently, electrical energy.
In order to achieve higher performing rotor blades with increased annual energy production, “flatback” airfoils have been tested and used for the inboard sections of blades. Compared to thick conventional, sharp trailing-edge airfoils, a flatback airfoil with the same thickness exhibits increased lift and reduced sensitivity to fouling. Conventionally, flatback airfoils are formed integrally with the rotor blade during the molding process and, thus, have only been available for newly manufactured rotor blades. However, U.S. Patent Application Publication Number 2010/0278657 (Kildegaard), entitled “Wind Turbine Blade and Blade Element Combination and Method of Changing the Aerodynamic Profile of a Wind Turbine Blade,” discloses a separate blade element that may be installed onto a rotor blade to create a truncated or flatback airfoil. Specifically, the blade element is installed onto a rotor blade such that a planar end surface of the blade element is directly aligned with the trailing edge, thereby creating a blunt trailing edge defining a perpendicular angle relative to the chord of the rotor blade. While such a blade element provides a means for creating a conventional flatback airfoil shape, it is desirable to provide rotor blades with modified flatback airfoil shapes to further enhance the overall performance of the blades.
Accordingly, an airfoil modifier that may be installed onto a rotor blade to create a modified flatback airfoil design would be welcomed in the technology.